DISPATCHES
Markers of Disease Severity in Patients with Spanish Influenza in the Japanese Armed Forces, 1919–1920 Koichiro Kudo, Toshie Manabe, Shinyu Izumi, Jin Takasaki, Yuji Fujikura, Akihiko Kawana, Kenji Yamamoto We examined preserved medical charts of 470 Spanish influenza patients (8 with fatal cases) hospitalized at former army hospitals in Japan during 1919–1920. The following factors were associated with longer periods of hospitalization: adventitious discontinuous lung sounds, maximum respiration rate, continuation of high fever after hospital admission, and diphasic fever.
T
he first and second waves of the Spanish influenza pandemic in Japan affected ≈21 million persons (257,000 deaths) and 2 million persons (127,000 deaths), respectively (1). Although available clinical techniques and treatment options for Spanish influenza patients were limited in this era, charts showing detailed records of lung sounds and fever exist and can be used to infer disease severity in affected persons. We aimed to identify physical features, including respiratory sounds, that might be associated with disease severity among patients in Japan who were affected by Spanish influenza during 1919 and 1920. The Study We analyzed medical charts preserved at the former First Army Hospital in Tokyo, Japan, and other affiliated hospitals. We previously described the clinical features of Spanish influenza among patients who were hospitalized at several study sites (2). Recently, additional records of patients affected by the second wave of disease during 1919–1920 were discovered, and these patients were the subjects of this study. A total of 470 patients hospitalized during January 1919–January 1920 and diagnosed with Spanish influenza Author affiliations: Koto Hospital, Tokyo, Japan (K. Kudo); Waseda University Organization for Regional and Inter-regional Studies, Tokyo (K. Kudo, T. Manabe); Teikyo University School of Medicine, Tokyo (T. Manabe); Tsukuba University Graduate School of Comprehensive Human Sciences, Ibaraki, Japan (T. Manabe); National Center for Global Health and Medicine, Tokyo (S. Izumi, J. Takasaki, K. Yamamoto); National Defence Medical College, Saitama, Japan (Y. Fujikura, A. Kawana); So-Yu Medical Foundation Institute of Medicine, Tokyo (K. Yamamoto) DOI: http://dx.doi.org/10.3201/eid2304.152097 662
(as “epidemic cold” or “pneumonia due to epidemic cold”) fit the criteria for inclusion in the study. All patients were male soldiers or officers in the military of Japan. We collected data concerning patients’ general background and physical assessments, including lung sounds and fever charts. Among all patients, 8 (2%) died. We divided the patients who survived (n = 462, 98%) into 3 groups on the basis of hospitalization length: 21 days (36%); we compared variables among the 3 groups. High fever was defined as a body temperature >38°C, and diphasic fever was defined as a body temperature >38°C after the initial fever had decreased to 21 days and among those who did not survive (Table 1). Factors associated with the length of hospitalization in survivors (identified by using a Cox hazard proportional model) included diphasic fever, >6 days of continuing high fever from admission, a maximum respiration rate >26 breaths/ min, and adventitious discontinuous lung sounds (Table 2). Conclusions The length of hospitalization of patients with acute infectious diseases, including Spanish influenza, is associated with disease severity. Otherwise healthy soldiers who became patients during the second wave of Spanish influenza in Japan during 1919–1920 were severely affected. Adventitious discontinuous lung sounds, rapid respiration rate, and time-course of fever reflected disease severity during the pandemic. Patients who were severely affected had mainly fulminating fatal cases or experienced secondary bacterial pneumonia. Severe disease associated with the recent pandemic caused by influenza A(H1N1)pdm09 virus can be attributed to viral pneumonia, superimposition of bacterial pneumonia,
Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 23, No.4, April 2017
Disease Severity in Spanish Influenza, 1919–1920
Table 1. General characteristics and clinical findings of patients with Spanish influenza during hospitalization, Japan, 1919–1920* Survivors, by hospitalization length, n = 462 Nonsurvivors, Characteristic/clinical feature n=8 21 d, n = 170 p value† Median age, y (IQR) 22 (21–23) 22 (21–28) 21 (20– 27) 21 (20–22)
Markers of Disease Severity in Patients with Spanish Influenza in the Japanese Armed Forces, 1919–1920 Koichiro Kudo, Toshie Manabe, Shinyu Izumi, Jin Takasaki, Yuji Fujikura, Akihiko Kawana, Kenji Yamamoto We examined preserved medical charts of 470 Spanish influenza patients (8 with fatal cases) hospitalized at former army hospitals in Japan during 1919–1920. The following factors were associated with longer periods of hospitalization: adventitious discontinuous lung sounds, maximum respiration rate, continuation of high fever after hospital admission, and diphasic fever.
T
he first and second waves of the Spanish influenza pandemic in Japan affected ≈21 million persons (257,000 deaths) and 2 million persons (127,000 deaths), respectively (1). Although available clinical techniques and treatment options for Spanish influenza patients were limited in this era, charts showing detailed records of lung sounds and fever exist and can be used to infer disease severity in affected persons. We aimed to identify physical features, including respiratory sounds, that might be associated with disease severity among patients in Japan who were affected by Spanish influenza during 1919 and 1920. The Study We analyzed medical charts preserved at the former First Army Hospital in Tokyo, Japan, and other affiliated hospitals. We previously described the clinical features of Spanish influenza among patients who were hospitalized at several study sites (2). Recently, additional records of patients affected by the second wave of disease during 1919–1920 were discovered, and these patients were the subjects of this study. A total of 470 patients hospitalized during January 1919–January 1920 and diagnosed with Spanish influenza Author affiliations: Koto Hospital, Tokyo, Japan (K. Kudo); Waseda University Organization for Regional and Inter-regional Studies, Tokyo (K. Kudo, T. Manabe); Teikyo University School of Medicine, Tokyo (T. Manabe); Tsukuba University Graduate School of Comprehensive Human Sciences, Ibaraki, Japan (T. Manabe); National Center for Global Health and Medicine, Tokyo (S. Izumi, J. Takasaki, K. Yamamoto); National Defence Medical College, Saitama, Japan (Y. Fujikura, A. Kawana); So-Yu Medical Foundation Institute of Medicine, Tokyo (K. Yamamoto) DOI: http://dx.doi.org/10.3201/eid2304.152097 662
(as “epidemic cold” or “pneumonia due to epidemic cold”) fit the criteria for inclusion in the study. All patients were male soldiers or officers in the military of Japan. We collected data concerning patients’ general background and physical assessments, including lung sounds and fever charts. Among all patients, 8 (2%) died. We divided the patients who survived (n = 462, 98%) into 3 groups on the basis of hospitalization length: 21 days (36%); we compared variables among the 3 groups. High fever was defined as a body temperature >38°C, and diphasic fever was defined as a body temperature >38°C after the initial fever had decreased to 21 days and among those who did not survive (Table 1). Factors associated with the length of hospitalization in survivors (identified by using a Cox hazard proportional model) included diphasic fever, >6 days of continuing high fever from admission, a maximum respiration rate >26 breaths/ min, and adventitious discontinuous lung sounds (Table 2). Conclusions The length of hospitalization of patients with acute infectious diseases, including Spanish influenza, is associated with disease severity. Otherwise healthy soldiers who became patients during the second wave of Spanish influenza in Japan during 1919–1920 were severely affected. Adventitious discontinuous lung sounds, rapid respiration rate, and time-course of fever reflected disease severity during the pandemic. Patients who were severely affected had mainly fulminating fatal cases or experienced secondary bacterial pneumonia. Severe disease associated with the recent pandemic caused by influenza A(H1N1)pdm09 virus can be attributed to viral pneumonia, superimposition of bacterial pneumonia,
Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 23, No.4, April 2017
Disease Severity in Spanish Influenza, 1919–1920
Table 1. General characteristics and clinical findings of patients with Spanish influenza during hospitalization, Japan, 1919–1920* Survivors, by hospitalization length, n = 462 Nonsurvivors, Characteristic/clinical feature n=8 21 d, n = 170 p value† Median age, y (IQR) 22 (21–23) 22 (21–28) 21 (20– 27) 21 (20–22)
